[{% for post in site.posts %}
  {
    "title"    : "{{ post.title | escape }}",
    "tags"     : "{% for tag in post.tags %}{% if forloop.rindex != 1 %}{{ tag }} {% else %}{{ tag }}{% endif %}{% endfor %}",
    "url"      : "{{ post.url | relative_url }}"
  } {% unless forloop.last %},{% endunless %}
{% endfor %}]